1. Field of the Invention
This invention relates to an image forming apparatus and, more particularly, to a multiplexing mechanism for transferring data on an exposure head from an image processing section to the exposure head.
2. Description of Related Art
In an image forming apparatus with use of an exposure head composed of a light emitting element array such as a light emitting diode (LED) array, data on the exposure head are generated at an image processing section and then transferred sequentially to the exposure head in order to be exposed. The image processing section and the exposure head are connected via a flexible cable composed of a flexible printed wiring board to transfer such parallel data on the exposure head as composed of multiple bits (i.e., four bits), a clock signal for triggering transfer or exposure of the data, and a control signal via different signal wires in parallel, respectively (see, e.g., Japanese Patent Laid-Open No. H11-34394).
Recent image forming apparatuses are required to improve more in speed and resolution. In association with the improvement in speed and resolution, the image forming apparatuses tend to have an increased mutual interference problem among the aforementioned signal wires or radiated noise problem. As a result, there have been inevitable problems such as extraordinary signal transmission due to the mutual interference among the signals, malfunction of peripheral circuits inside the apparatus due to generation of the radiated noise, and adverse effects on an exterior of the apparatus, or the like.
Problem to be solved is that excessive digital noise is generated to cause malfunction or peripheral circuits inside the apparatus or to become such EMI noise (radiated noise) as having the adverse effects on the exterior of the apparatus since the parallel data on the exposure head composed of multiple bits, the clock signal for triggering transfer or exposure of the data, and the control signal are respectively transferred via different signal wires.